1. Tardigrade
  2. Question
  3. Chemistry
  4. When hydrochloric acid is added to cobalt nitrate solution at room temperature, the following reaction takes place and the reaction mixture becomes blue. On cooling the mixture, it becomes pink. On the basis of this information mark the correct answer. underset textPink[Co(H2O)6]3+(aq) + 4Cl-(aq) leftharpoons underset textBlue[CoCl4]2-(aq) + 6H2O(l)

Question Error Report

Thank you for reporting, we will resolve it shortly

Back to Question

Q. When hydrochloric acid is added to cobalt nitrate solution at room temperature, the following reaction takes place and the reaction mixture becomes blue. On cooling the mixture, it becomes pink. On the basis of this information mark the correct answer.
$\underset{\text{Pink}}{[Co(H_2O)_6]^{3+}_{(aq)}} + 4Cl^{-}_{(aq)} \rightleftharpoons \underset{\text{Blue}}{[CoCl_4]^{2-}_{(aq)}} + 6H_2O_{(l)}$

Equilibrium

Solution:

$\underset{\text{Pink}}{[Co(H_2O)_6]^{3+}_{(aq)}}+ 4Cl^{-}_{(aq)} \rightleftharpoons \underset{\text{Blue}}{[CoCl_4]^{2-}_{(aq)}} + 6H_2O_{(l)}$
On cooling the mixture, the reaction proceeds in backward direction and on heating the mixture, the reaction proceeds in forward direction, hence, the reaction is endothermic i.e., $\Delta H > 0$